Chain saw

ABSTRACT

Disclosed herein is a chain saw in which the front and rear handles and a tank assembly are rigidly connected to a frame to form an integrated frame assembly. A separate power unit including an engine and a cutter bar is supported from one side of the tank assembly by vibration absorbing means to thereby minimize the transmission of vibrations generated by the engine and the cutter bar to the handles.

"United, States Patent 1191 Kolorz 1 1 Nov. 26, 1974 CHAIN SAW 3,651,839 3/1972 $11111 etal 30/381 [75] Inventor: V Bruno K010, e o t Bridg 3,680,608 8/1972 Emmench et al. 30/381 Ontario, Canada Assignee: Outboard Marine Corporation,

Waukegan, Ill.

[22] Filed: Jan. 2, 1974 [21] Appl. N0.: 429,929

[52] US. Cl. 30/381, 173/162 [51] Int. Cl; B27b 17/02 [58] Field of Search 30/381, 380, 383; 173/162 [56] References Cited UNITED STATES PATENTS 3,525,373 8/1970 Kobayashi 30/381 3,542,095 11/1970 Frederickson et al. 30/381 Primary Examiner-Al Lawrence Smith Assistant Examiner-Roscoe V. Parker Attorney, Agent, or Firm-Michael, Best & Friedrich [5 7] ABSTRACT Disclosed herein is a chain saw in which the front and rear handles and a tank assembly are rigidly connected to a frame to form an integrated frame assembly. A separate power unit including an engineand a cutter bar is supported from one side of the tank as sembly-by vibration absorbing means to thereby minimize the transmission of vibrations generated by the engine and the cutter bar to the handles.

12 Claims, 3 Drawing Figures CHAIN SAW BACKGROUND OF THE INVENTION This invention relates to chain saws and, more particularly, to chain saws having an improved vibration isolation system.

Considerable effort has been devoted to damp the level of vibrations transmitted to an operator of a portable chain saw. Various vibration isolating arrangements have been provided for portable chain saws. Examples of prior vibration isolation arrangements for portable chain saws are disclosed in the following US. patents:

Inventor Patent No. Issued Kobayashi ct al 3,700,015 October 24, I972 Frederickson et al 3,698,455 October 17, I972 Emmerich et 211 3,680,608 August 1, 1972 Stihl et al 3,651,839 March 28, 1972 Sherwood et al 3,637,029 January 25, 1972 Frederickson et al 3,542,095 November 24, 1972 Scharpf 3,530,908 September 29, 1970 Kobayashi 3,525,373 August 25. 1970 Rauh 3,409,056 November 5, 1968 Irgens 3,372,718 March 12. 1968 Dobbertin et al 3,244,473 December 21,1965

SUMMARY OF THE INVENTION This invention provides achain saw comprising a frame assembly including front and rear handles connected to a tank assembly and a separate power unit which includes an engine and a cutter bar end and l which is resiliently supported from one side of the tank assembly.

More particularly, the invention provides a chain saw in which the front and rear handles, an upper frame member, and a tank assembly including an integral gas tank are rigidly interconnected to form an integrated frame assembly. The engine and the cutter bar are mounted on a support frame which is supported from one side of the tank assembly through three co-planar vibration absorbing mounts. These mounts are interposed the support frame and the tank assembly and are arranged in a generally triangular pattern around the axis of rotation of a drive shaft which is drivingly connected to the cutting chain. With this arrangement, vibrations generated by the engine and the cutter bar are effectively vibrationally isolated from the handles. The transmission of vibrations to the operator are further minimized because the handles are connected to the tank assembly which is a relatively resilient mass and provides additional damping. 1 The vibrationabsorbing mounts are preferably located with the center of one being below and rearward of the drive shaft axis, one being located below and forward of the drive shaft axis, and one being located above and forward of the drive shaft axis. Each of the mounts preferably is comprised of a pair of longitudinally spaced, elastomeric mounting elements.

One of the features of the invention is to provide a portable chain saw having a simply arranged vibration isolation system.

Another feature of the invention is to provide a chain saw wherein the front and rear handle and the gas tank assembly are rigidly interconnected to form a frame assembly'and the engine and cutter bar are included in a separate power unit which is supported from the tankassembly by vibration absorbing mounts to minimize the transmission vibrations generated by the engine and the cutter bar to the handles.

Other features and aspects of the invention will be come apparent upon reviewing the following detailed description, the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side view, partially broken away, of a chain saw embodying various of the features of the invention.

FIG. 2 is a front view, partially broken away and in section, of the chain saw shown in FIG. 1.

FIG. 3 is a side view of the frame assembly incorporated in the chain saw shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawing. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purposes of description and should not be regarded as limiting.

Illustrated in the drawings is a chain saw 10 including a frame assembly 12 and a power unit 14 which is resiliently mounted to the frame assembly 12.

The frame assembly 12 includes a generally horizontally extending upper frame member 16, a generally U- shaped, longitudinally extending rear handle 18 rigidly The tank assembly 32 includes a hollow forward portion defining a gas tank 34-(shown schematically in dotted outline in FIG. 3) which has a capped supply port 36 and a hollow rear portion defining an oil tank 38 (shown schematically in dotted outline in FIG. 3) which has a capped supply port 40. The tank assembly 32 has a generally vertical side portion 41 from which the power unit14 is supported as explained below.

The lower end 42 of the rear handle 18 is rigidly connected to the rear end portion 43 of the tank assembly 32 and the lower end 44 of the front handle 24 is rigidly secured to the lower, front end portion of the tank assembly 32, such as by bolts 48. Thus, the upper frame member 16, the rear handle 18, the front handle 24 and the tank assembly 32 are rigidly interconnected and form integral parts of the frame'assembly 12.

her 16, the tank assembly 32, and the vertical frame member 50.

The power unit 14 includes an endless, link-type cutting chain 54 carried on a generally planar, vertically disposed cutter bar 56. The cutter bar 56 is bolted or otherwise rigidly secured to a support frame 58 having a generally vertical side portion 59. The cutting chain 54 is trained about the periphery of the cutter bar 56 in the usual manner.

Mounted on the support frame 58 for driving the cutting chain 54 is an internal combustion engine 60 including an engine block 62 and a piston 64 which reciprocates along an axis extending longitudinally and parallel with the plane of the cutter bar 56. The engine piston 64 is drivingly connected to a drive shaft 66 which is rotatably mounted in the engine block for rotation about an axis (designated by reference numeral 68) which is perpendicular to the plane of the cutter bar 56. Power is supplied to the cutting chain 54 by a sprocket 70 which is located on one end of the drive shaft 66 and about which the cutting chain 54 is trained. The engine 60 extends into the frame assembly opening 52 which is somewhat larger than the outer dimensions of the engine 60 so there is no metal-to-metal contact between theengine 60 and the frame assembly 12.

In accordance with the invention, vibration absorbing means are provided for supporting the power unit 14 from the side portion 41 of and in juxtaposition with the tank assembly 32 so as to minimize the transmission of vibrations generated by the engine 60 and the cutting chain 54 to the front and rear handles 24 and 18. While various arrangements can be used, in the specific construction illustrated, the mounting means comprises three co-planar elastomeric mounts 72A, 72B, and 72C which are interposed the side portion 41 of the tank assembly 32 and the side portion 59 of the support frame 58 and which are arranged in a generally triangular pattern about the drive shaft axis 68.

More specifically, each of the mounts 72A, 72B, and

72C includes a pair of longitudinally spaced mounting elements 74 made from an elastomeric material, such as rubber. Referring to FIG. 2, fixedly secured in each of the mounting elements 74 is a pair of oppositely disposed, threaded studs 76 and 78. The side portion 41 of the tank assembly 32 includes a series of recesses 80 which receive one end of a respective mounting element 74 and the side portion 59 of the support frame 58 includes a series of recesses 82 which are laterally aligned with recesses of 80 on the tank assembly 32 and receive the opposite end of a respective mounting element 74. Each of the mounting element studs 76 is threaded into a tapped cavity 84 provided in respective recesses 80 on the tank assembly 32 and each of the mounting element studs 78 extend through a hole 86 provided in respective recesses 82 on the support frame 58. A nut 88 is threaded onto the outer end of each of the mounting element threads 78 to fasten the support frame 58 to the mounting elements 74.

With this arrangement, the power unit 14 is supported from the tank assembly 32 through the mounting elements 74 to thereby minimize the transmission of vibrations generated by the engine 60 and the cutter blade 56 to the front and rear handles 24 and 18. By connecting both ends of the rear handle 18 and the front handle 24 to the tank assembly 32 and locating the tank assembly 32 between the handles and the mounting elements 74 in accordance with the invention, the transmission of vibrations to the operator is further minimized. The tank assembly 32, by virtue of its hollow construction, is a relatively resilient mass and thereby damps any vibrations transmitted thereto through the mounting elements 74.

As mentioned above, the vibration absorbing mounts 72A, 72B and 72C are arranged in a generally triangular pattern about the drive shaft axis 68. In order to provide maximum absorption of the multi-directional vibrations emananting from the engine and the cutter bar 56, the center of at least one of the mounts is located rearwardly of the drive shaft axis 68, the center of at least one of the mounts is located forward of the drive shaft axis 68, the center of at least one of the mounts is located above the drive shaft axis 68, and the center of at least one of the mounts is located below the drive shaft axis 68. While various arrangements can be used, in the preferred construction illustrated, the center of the two mounting elements 74 forming the mount 72A is located below and rearward of the drive shaft axis 68, the center of the two mounting elements 74 forming the mount 72B is located below and forward of the drive shaft axis 68, and the center of the two mounting elements 74 forming the mount 72C is located above and forward of the drive shaft axis 68. It is within the scope of the invention to employ a single mounting element 74 for each of the mounts 72A, 72B,

and 72C. I

As mentioned above, the engine 60 is received within the frame assembly opening 52 so there is no metal-tometal contact between the engine and the frame assembly, thereby avoiding the transmission of engine vibrations to the frame assembly 32. In order to further avoid the transmission of vibrations, all connections between the engine 60 and the auxiliary equipment carried on the frame assembly 32 are preferably constructed from a resilient, shock absorbing material.

In the construction illustrated, the engine carburetor (not shown) is mounted on the engine block 62 and is connected to the gas tank 34 by a flexible conduit (not shown), such as a rubber hose, the engine air filter 90 is mounted on the upper frame member 16 and is connected to the engine carburetor by a flexible conduit (not shown), and the oil tank 38 is connected by a flexible conduit (not shown) to an oil pump (not shown) which is mounted on the engine block 62 and is powered by the drive shaft 66. An engine starting device 92, such as a rewind starter, is mounted on the drive shaft 66 on the end opposite to the sprocket and is housed inside a shroud 94 mounted on the tank assembly 32. A pull rope 96 operatively connected to the starting device 92 represents the only physical contact between the starting device and the shroud.

Various features of the invention are set forth in the following claims:

1. A chain saw comprising a power unit including a generally vertically extending support frame, a vertically extending cutter bar mounted on said support frame, a cutting chain carried on said cutter bar, and an engine mounted on said support frame for driving said cutting chain, a tank assembly including an integral gas tank and a generally vertical side portion juxtaposed said support frame, a longitudinally extending rear handle connected to said tank assembly, a generally transversely extending front handle connected to said tank assembly, and resilient mounting means interposed said support frame and said tank assembly for supporting said power unit from said tank assembly and for vibrationally isolating said engine and said cutter bar from said handles.

2. A chain saw according to claim 1 including a generally horizontally extending upper frame member having forward and rear end portions, the forward end of said upper frame member being connected to said tank assembly, said rear handle having an upper end which is connected to the rear end portion of said upper frame member and a lower end which is connected to said tank assembly, and said front handle having an upper end which is connected to the forward end portion of said upper frame member and a lower end which is connected to said tank assembly.

3. A chain saw according to claim 2 wherein said tank assembly is generally L-shaped, extends down wardly and rearwardly from the forward end portion of said upper frame member, and terminates in a lower rear portion which is connected to the lower end of said rear handle.

4. A chain saw according to claim 2 wherein said upper frame member, said tank assembly, and said rear handle are arranged to define an opening therebetween for accommodating said engine, said opening being larger than the outer dimensions of said engine.

5. A chain saw according to claim 4 including a generally vertical frame member extending between and rigidly connecting the rear portions of said upper frame member and said tank assembly.

6. A chain saw according to claim 2 wherein said engine includes a crankshaft drivingly connected to a drive shaft which is mounted on said support frame for rotation about a transverse axis and is drivingly connected to said cutting chain, and said mounting means includes three elastomeric mounts which are co-planar and are arranged in a generally triangular pattern about said drive shaft axis with the center of at least one of said mounts being located forward of said drive shaft axis, the center of at least one of said mounts being located rearward of said drive shaft axis, the center of at least one of said mounts being located below said drive shaft axis, and the center of at least one of said mounts being located above said drive shaft axis.

7. A chain saw according to claim 6 wherein the cen-' ter of one of said mounts is located below and rearward of said drive shaft axis, the center of another of said mounts is located above and forward of said drive shaft axis, and the center of still another of said mounts is located below and forward of said drive shaft axis.

8. A chain saw according to claim 7 wherein each of said mounts includes a pair of longitudinally spaced, elastomeric mounting elements, each of said mounting elements being secured respectively at the opposite ends to said tank assembly and said support frame.

9. A chain saw comprising a power unit including a generally vertically extending support frame, a vertically extending cutter bar mounted on said support frame, a cutting chain carried on said cutter bar, and an engine mounted on said support frame and including a crankshaft drivingly connected to a drive shaft which is mounted on said support frame for rotation about a transverse axis and is drivingly connected to said cutting chain, a generally horizontally extending upper frame member having forward and rear end portions, a generally L-shaped tank assembly including an integral gas tank and a generally vertical side portion juxtaposed said support frame, said tank assembly being connected at the upper end to the forward end portion of said upper frame member, extending downwardly and rearwardly from the forward end portion of said upper frame member, and terminating in a lower rear portion, a longitudinally extending, rear handle having an upper end which is connected to the rear end portion of said upper frame member and a lower end which is connected to the lower rear portion of said tank assembly, a generally transversely extending front handle having an upper end which is connected to the forward end portion of said upper frame member and a lower end which is connected to said tank assembly, and three co-planar elastomeric mounts interposed said support frame and said tank assembly for supporting said power unit from said tank assembly and for vibrationally isolating said engine and said cutter bar from saidhandles, said elastomeric mounts being arranged in a generally triangular pattern about said drive shaft axis with the center of at least one of said mounts being located forward of said drive shaft axis, the center of at least one of said mounts being located rearward of said drive shaft axis, the center of at least one of said mounts being located below said drive shaft axis, and the center of at least one of said mounts being located above said drive shaft axis.

10. A chain saw according to claim 9 including a generally vertical frame member extending between and rigidly connecting the rear end portion of said upper frame member and the lower rear portion of said tank assembly, said upper frame member, said tank assembly and said vertical frame member defining an opening for accommodating said engine, said opening being somewhat larger than the outer dimensions of said engine.

11. A chain saw according to claim 10 wherein the center of one of said mounts is located below and rearward of said drive shaft axis, the center of another of said mounts is located above'and forward of said drive shaft axis, and the center of still another of said mounts is located below and forward of said drive shaft axis.

12. A chain saw according to claim 11 wherein each i of said mounts includes a pair of longitudinally spaced,

ends to said tank assembly and said support frame.

a: s =l= 

1. A chain saw comprising a power unit including a generally vertically extending support frame, a vertically extending cutter bar mounted on said support frame, a cutting chain carried on said cutter bar, and an engine mounted on said support frame for driving said cutting chain, a tank assembly including an integral gas tank and a generally vertical side portion juxtaposed said support frame, a longitudinally extending rear handle connected to said tank assembly, a generally transversely extending front handle connected to said tank assembly, and resilient mounting means interposed said support frame and said tank assembly for supporting said power unit from said tank assembly and for vibrationally isolating said engine and said cutter bar from said handles.
 2. A chain saw according to claim 1 including a generally horizontally extending upper frame member having forward and rear end portions, the forward end of said upper frame member being connected to said tank assembly, said rear handle having an upper end which is connected to the rear end portion of said upper frame member and a lower end which is connected to said tank assembly, and said front handle having an upper end which is connected to the forward end portion of said upper frame member and a lower end which is connected to said tank assembly.
 3. A chain saw according to claim 2 wherein said tank assembly is generally L-shaped, extends downwardly and rearwardly from the forward end portion of said upper frame member, and terminates in a lower rear portion which is connected to the lower end of said rear handle.
 4. A chain saw according to claim 2 wherein said upper frame member, said tank assembly, and said rear handle are arranged to define an opening therebetween for accommodating said engine, said opening being larger than the outer dimensions of said engine.
 5. A chain saw according to claim 4 including a generally vertical frame member extending between and rigidly connecting the rear portions of said upper frame member and said tank assembly.
 6. A chain saw according to claim 2 wherein said engine includes a crankshaft drivingly connected to a drive shaft which is mounted on said support frame for rotation about a transverse axis and is drivingly connected to said cutting chain, and said mounting means includes three elastomeric mounts which are co-planar and are arranged in a generally triangular pattErn about said drive shaft axis with the center of at least one of said mounts being located forward of said drive shaft axis, the center of at least one of said mounts being located rearward of said drive shaft axis, the center of at least one of said mounts being located below said drive shaft axis, and the center of at least one of said mounts being located above said drive shaft axis.
 7. A chain saw according to claim 6 wherein the center of one of said mounts is located below and rearward of said drive shaft axis, the center of another of said mounts is located above and forward of said drive shaft axis, and the center of still another of said mounts is located below and forward of said drive shaft axis.
 8. A chain saw according to claim 7 wherein each of said mounts includes a pair of longitudinally spaced, elastomeric mounting elements, each of said mounting elements being secured respectively at the opposite ends to said tank assembly and said support frame.
 9. A chain saw comprising a power unit including a generally vertically extending support frame, a vertically extending cutter bar mounted on said support frame, a cutting chain carried on said cutter bar, and an engine mounted on said support frame and including a crankshaft drivingly connected to a drive shaft which is mounted on said support frame for rotation about a transverse axis and is drivingly connected to said cutting chain, a generally horizontally extending upper frame member having forward and rear end portions, a generally L-shaped tank assembly including an integral gas tank and a generally vertical side portion juxtaposed said support frame, said tank assembly being connected at the upper end to the forward end portion of said upper frame member, extending downwardly and rearwardly from the forward end portion of said upper frame member, and terminating in a lower rear portion, a longitudinally extending rear handle having an upper end which is connected to the rear end portion of said upper frame member and a lower end which is connected to the lower rear portion of said tank assembly, a generally transversely extending front handle having an upper end which is connected to the forward end portion of said upper frame member and a lower end which is connected to said tank assembly, and three co-planar elastomeric mounts interposed said support frame and said tank assembly for supporting said power unit from said tank assembly and for vibrationally isolating said engine and said cutter bar from said handles, said elastomeric mounts being arranged in a generally triangular pattern about said drive shaft axis with the center of at least one of said mounts being located forward of said drive shaft axis, the center of at least one of said mounts being located rearward of said drive shaft axis, the center of at least one of said mounts being located below said drive shaft axis, and the center of at least one of said mounts being located above said drive shaft axis.
 10. A chain saw according to claim 9 including a generally vertical frame member extending between and rigidly connecting the rear end portion of said upper frame member and the lower rear portion of said tank assembly, said upper frame member, said tank assembly and said vertical frame member defining an opening for accommodating said engine, said opening being somewhat larger than the outer dimensions of said engine.
 11. A chain saw according to claim 10 wherein the center of one of said mounts is located below and rearward of said drive shaft axis, the center of another of said mounts is located above and forward of said drive shaft axis, and the center of still another of said mounts is located below and forward of said drive shaft axis.
 12. A chain saw according to claim 11 wherein each of said mounts includes a pair of longitudinally spaced, elastomeric mounting elements, each of said mounting elements being secured respectively at the opposite ends to said tank assembly and said support frame. 